From db0d5f51e4eb675aec1d5a8ba3600503bab9fb12 Mon Sep 17 00:00:00 2001
From: teidesu <me@tei.su>
Date: Mon, 10 May 2021 17:30:05 +0300
Subject: [PATCH] feat(dispatcher): filtering for service messages, by chat
 type and for text-only msgs

---
 packages/client/src/types/messages/message.ts |  7 +++
 packages/dispatcher/src/filters.ts            | 43 ++++++++++++++++---
 2 files changed, 43 insertions(+), 7 deletions(-)

diff --git a/packages/client/src/types/messages/message.ts b/packages/client/src/types/messages/message.ts
index 692575e3..9a74b8ae 100644
--- a/packages/client/src/types/messages/message.ts
+++ b/packages/client/src/types/messages/message.ts
@@ -164,6 +164,13 @@ export class Message {
         return this.raw.out!
     }
 
+    /**
+     * Whether this message is a service message
+     */
+    get isService(): boolean {
+        return this.raw._ === 'messageService'
+    }
+
     /**
      * Multiple media messages with the same grouped ID
      * indicate an album or media group
diff --git a/packages/dispatcher/src/filters.ts b/packages/dispatcher/src/filters.ts
index 6f8b4897..ef3d5d7e 100644
--- a/packages/dispatcher/src/filters.ts
+++ b/packages/dispatcher/src/filters.ts
@@ -14,17 +14,19 @@ import {
     RawDocument,
     Sticker,
     TelegramClient,
-    User, Venue,
+    User,
+    Venue,
     Video,
     Voice,
     Poll,
     Invoice,
     Game,
-    WebPage
+    WebPage,
 } from '@mtcute/client'
 import { MaybeArray } from '@mtcute/core'
 import { ChatMemberUpdate } from './updates'
 import { ChosenInlineResult } from './updates/chosen-inline-result'
+import { MessageAction } from '@mtcute/client/src/types/messages/message-action'
 
 /**
  * Type describing a primitive filter, which is a function taking some `Base`
@@ -294,12 +296,12 @@ export namespace filters {
         msg.sender instanceof User && msg.sender.isBot
 
     /**
-     * Filter messages sent in broadcast channels
+     * Filter messages by chat type
      */
-    export const channel: UpdateFilter<
-        Message,
-        { chat: Modify<Chat, { type: 'channel' }> }
-    > = (msg) => msg.chat.type === 'channel'
+    export const chat = <T extends Chat.Type>(
+        type: T
+    ): UpdateFilter<Message, { chat: Modify<Chat, { type: T }> }> => (msg) =>
+        msg.chat.type === type
 
     /**
      * Filter incoming messages.
@@ -332,6 +334,33 @@ export namespace filters {
         { media: Exclude<Message['media'], null> }
     > = (msg) => msg.media !== null
 
+    /**
+     * Filter text-only messages non-service messages
+     */
+    export const text: UpdateFilter<
+        Message,
+        {
+            media: null
+            isService: false
+        }
+    > = (msg) => msg.media === null && !msg.isService
+
+    /**
+     * Filter service messages
+     */
+    export const service: UpdateFilter<Message, { isService: true }> = (msg) =>
+        msg.isService
+
+    /**
+     * Filter service messages by action type
+     */
+    export const action = <T extends Exclude<MessageAction, null>['type']>(
+        type: T
+    ): UpdateFilter<
+        Message,
+        { action: Extract<MessageAction, { type: T }> }
+    > => (msg) => msg.action?.type === type
+
     /**
      * Filter messages containing a photo
      */